US8756789B2 - Method of manufacturing a catheter assembly - Google Patents

Abstract

A catheter assembly includes a catheter having a proximal end and a distal end; an expandable device releasably attached to the catheter near the distal end; a generally tubular constraining sleeve extending around and compressing the device to an outer peripheral dimension suitable for endoluminal delivery; a tip fixedly secured to the distal end of the catheter; and a bridge member disposed between the tip and the expandable device so as to fill a gap therebetween as the catheter assembly is bent during endoluminal delivery of the expandable device to a treatment site.

Description

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a non-provisional of, and claims priority to, U.S. Provisional Patent Application No. 61/414,270, entitled “Medical Apparatus and Method of Making The Same,” filed Nov. 16, 2010, the content of which is hereby incorporated by reference in its entirety.

BACKGROUND

1. Field

The present disclosure relates to catheter-based systems used to deliver medical devices.

2. Discussion of the Related Art

Various medical devices require catheter based delivery systems. Such medical devices include implantable, diagnostic and therapeutic devices. Common implantable, endovascular devices can include stents, stent grafts, filters, occluders, sensors and other devices. Endovascular devices are commonly advanced through the native vasculature to a treatment site by the use of a flexible catheter. When properly positioned at the treatment site the device (in the case of a stent) can be expanded to appose the vasculature. The device can then be released from the catheter allowing the catheter to be withdrawn from the vasculature. It is desirable to pre-compact endovascular devices into small delivery profiles in order to minimize vascular trauma and enhance maneuverability through torturous anatomies. A highly compacted device is often relatively stiff and is therefore difficult to bend into a small radius. A soft, flexible “olive” or tip is commonly positioned distal to the compacted device at the leading end of the delivery catheter, again to minimize vascular trauma and to enhance the positioning accuracy. As the device is advanced through a curved vessel, the junction between the relatively stiff compacted device and the soft flexible tip can “open up” presenting a gap.

It remains desirable to have a device delivery system incorporating a means to cover any potential gap between the compacted device and a leading catheter tip.

BRIEF DESCRIPTION OF THE DRAWINGS

In the following drawings:

FIG. 1 is a cross-sectional view of a catheter assembly in accordance with various embodiments with a bridging member shown in an uncompressed state between a distal tip and device of the catheter assembly.

FIG. 2 is a cross-sectional view of the catheter assembly inFIG. 1 with the bridging member shown in a compressed state between the distal tip and catheter assembly.

FIG. 3 is a cross-sectional view of the bridging member ofFIG. 1 in the uncompressed state.

FIG. 4 is a cross-sectional view of the bridging member ofFIG. 1 in the compressed state.

FIG. 5 is a side view of a catheter assembly in accordance with various embodiments.

FIG. 6 is a perspective view of a bridging member of the catheter assembly shown inFIG. 5.

FIG. 7 is side view of a catheter assembly according to various embodiments.

FIG. 8 is a perspective view of the a bridging member of the catheter assembly shown inFIG. 7.

FIG. 9 is a perspective view of a bridging member in accordance with various embodiments.

FIG. 10 is an enlarged perspective view of the bridging member inFIG. 9.

FIG. 11 is an enlarged perspective view of a catheter assembly incorporating the bridging member inFIG. 9 and a protective outer sleeve cutting blade.

DETAILED DESCRIPTION

Referring toFIGS. 1 and 2, a catheter assembly in accordance with various embodiments is shown and generally indicated at10. Thecatheter assembly10 includes acatheter20, anexpandable device30, a generally tubular restraining member or “constraining sleeve”40 and atip50. Thecatheter20 extends longitudinally between opposite proximal22 and distal24 ends. Theexpandable device30 is releasably attached to thecatheter20 near thedistal end24 of thecatheter20. The constrainingsleeve40 is disposed around and compresses thedevice30 to an outer peripheral dimension suitable for endoluminal delivery to a treatment site in a patient. The constrainingsleeve40 has adistal end42 that faces thedistal end24 of thecatheter20. Examples of restraining members or constraining sleeves for releasably maintaining expandable devices in a collapsed state for endoluminal delivery can be found in U.S. Pat. No. 6,352,561 to Leopold et al, the content of which is incorporated herein by reference in its entirety. Described in greater detail below, thecatheter assembly10 further includes abridge member60 disposed generally between thetip50 and theexpandable device30 to fill a gap therebetween.

InFIG. 1, thebridge member60 is shown positioned along a gap “G” between thetip50 and thedevice30. Thebridge member60, as shown, is not yet fully assembled to thecatheter assembly10 and is in an uncompressed state (also illustrated inFIG. 3). During assembly of thecatheter assembly10, thedevice30 is positioned along thecatheter20 and compressed or crushed onto the catheter by the constrainingsleeve40 so as to have an outer peripheral dimension suitable for endoluminal delivery. Thebridge member60 includes abore62 through which thedistal end24 of thecatheter20 is inserted. Thetip50 is then placed onto thedistal end24 of thecatheter20. Thetip50 is pressed axially toward thedevice30, and thebridge member60 is compressed generally axially between thetip50 and thedevice30, as shown inFIG. 2. Thetip50 is fixedly secured to thedistal end24 of thecatheter20 and thereby retains thebridge member60 in the compressed state (also illustrated inFIG. 4). Thetip50 may be fixedly secured to thedistal end24 of thecatheter20 by a variety of fixing methods, such as by using UV-cured adhesives, ultrasonic welding, reflow bonding, press fits, or other joining methods known in the art.

In one embodiment, thebridge member60 is compressed elastically between thetip50 and thedevice30 so that as thecatheter assembly10 is bent, such as during endoluminal delivery, thebridge member60 continues to fill the gap between the tip5 and thedevice30 as well as maintain a generally continuous,transitional surface64 therebetween. More specifically, as thecatheter assembly10 is bent, thebridge member60 is further compressed along an inner curve of the bend and at the same time allowed to expand or relax along an outer curve of the bend.

InFIGS. 5 and 6, an alternative embodiment of a catheter assembly is shown and generally indicated at110. Thecatheter assembly110 of this embodiment includes a generallytubular bridge member160 having a lumen orbore162 defined by a generallycylindrical side wall166. Theside wall166 may be constructed of ePTFE, or other materials such as FEP, PET, or other medical grade flexible polymers. Thebridge member160 also includes awire frame168. Thewire frame168 may be formed from Nitinol. Alternatively, the wire frame may be formed from L605, 304V, MP35N, 316L, or any other medical grade allow. Thewire frame168 may have a generally sinusoidal shape extending peripherally about theside wall166. The wire frame may also be formed into other shapes depending on the specific treatment needs.

Referring specifically toFIG. 5, thetip150 may include acircumferential groove153 onto which thebridge member160 can be coupled or secured to thetip150. For example, a releasable shrink tube may be applied about thebridge member160 along thegroove153 to secure thebridge member160 to thetip150.

InFIGS. 7 and 8, another alternative embodiment of a catheter assembly is shown and generally indicated at210. Thecatheter assembly210 of this embodiment includes a generally cylindrical or tubeshaped bridge member260 having an a longitudinally extendingslot268. Thebridge member260 is formed from a metal or metal alloy, such as Nitinol, L605, 304V, MP35N, 316L, or any other medical grade allow. In assembly, theslot268 allows thebridge member260 to be expanded radially and elastically to allow insertion of a proximal end of thetip250 through thebridge member lumen262. Thebridge member260 is then allowed to return toward its untensioned state and contract toward its untensioned dimension, thereby coupling thebridge member260 to thetip250. As in the previous embodiments, thebridge member260 fills the gap between thetip250 and thedevice230, even as thecatheter assembly210 is bent during endoluminal delivery. Thebridge member260 includes a generally pointed or narrowingproximal tip270 that facilitates retraction of thecatheter assembly210 through a sheath (not shown).

A catheter assembly in accordance with various embodiments is shown illustratively inFIGS. 9-11. Referring toFIG. 9, a partial view of a proximal end of adelivery system900 is shown for positioning a compactedmedical device902. Themedical device902 is constrained by atubular sleeve903 and is adjacent to adelivery catheter906. Covering thecompacted device902 and thetubular sleeve903 is aprotective sleeve904. Theprotective sleeve904 provides a smooth outer surface to thedelivery system900, enhancing device positionability and compatibility with a distal hemostatic valve (not shown). Also shown is a catheterproximal tip908.FIG. 10 is an enlarged view of the proximal end of the delivery system ofFIG. 9. Shown is a compactedmedical device902, tubular constrainingsleeve903, aproximal catheter tip908 and a protectiveouter sleeve904. The protectiveouter sleeve904 is shown releasably attached909 to theproximal catheter tip908. Agap910 is shown between theproximal catheter tip908 and the compactedmedical device902. A series of semi-rigid bridge straps912 are shown spanning thegap910. The bridge straps can be embedded into the protectiveouter sleeve904. The bridge straps912 provide a smooth transition between theproximal catheter tip908 and the compactedmedical device902. The bridge straps912 also allow the junction between theproximal catheter tip908 and the compactedmedical device902 to flex when thedelivery system900 traverses torturous anatomy. Prior to device deployment, the protectiveouter sleeve904 can be withdrawn by everting the sleeve back onto itself. The protectiveouter sleeve904 can be everted by applying tension to the sleeve end as shown bydirection arrows914. The tension can be applied by pull lines or other means attached to the proximal end of the protectiveouter sleeve904. When adequate tension is applied to the protectiveouter sleeve904 thereleasable attachment909 is released allowing the sleeve to evert. The releasable attachment can be an adhesive join, or use other releasable attachment means as commonly known in the art. Asfurther tension914 is applied, the protectiveouter sleeve904 further everts as shown inFIG. 11. The semi-rigid bridge straps912 (embedded into the protective outer sleeve904) bend and become reversed as shown inFIG. 11. The semi-rigid bridge straps912 can optionally incorporate pointed or chamfered leading ends916. The chamfered leading ends916 will allow anoptional cutting blade918 to self-align to the gaps between the semi-rigid bridge straps912 allowing the protectiveouter sleeve904 to be longitudinally split. The split protectiveouter sleeve904 can be subsequently fully removed from the catheter system. Semi-rigid bridge straps912 can be fabricated from a variety of metallic or polymeric materials as commonly known in the art.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the invention. Thus, it is intended that the present invention cover the modifications and variations of this invention provided they come within the scope of the appended claims and their equivalents.

Claims (5)

What is claimed is:

1. A method of manufacturing a catheter assembly including:

providing a catheter having a distal end and an expandable device fixedly secured thereto;

providing a bridge member generally coaxial with the catheter and disposed onto an exposed portion of the distal end of the catheter;

providing a tip generally coaxial with the catheter and disposed onto the exposed portion of the distal end of the catheter;

axially compressing the bridge member between the expandable device and the tip; and

fixedly securing the tip to the catheter to retain the bridge member in the compressed state between the expandable device and the tip.

2. The method as set forth inclaim 1 including axially compressing the bridge member toward the device so as to outwardly radially tension the expandable device.

3. The method as set forth inclaim 1 including compressing the expandable device with an outer constraining sleeve to an outer dimension suitable for endoluminal delivery.

4. The method as set forth inclaim 3 including axially compressing the bridge member toward the device to cause outward displacement of the bridge member to a desired outer profile.

5. The method as set forth inclaim 3 including axially compressing the bridge member toward the device to cause outward displacement of the bridge member to an outer profile that provides a transition between the tip and the expandable device.

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